Letter from the Secretary of the Treasury, transmitting a report of the directors of the Mint, of assays made of several species of foreign silver coins
U.S. Mint Reports (1821)
A second copy of the Mint Director (Robert Patterson) report on the assay of foreign coins. The same text is found in the American State Papers, finance (class 3), volume 3, report no. 610.
Paul Hybert summary: "An assay of foreign coins, from mint director Patterson to Treasury Secretary Crawford, who relayed it to Congress. Gold coins are not listed, as they no longer are current."
A transcription is at: http://www.chicagocoinclub.org/lib/us/asp/cl03.finance/v3/n610.html.